*keyword “might” be, but Scotus can say “that was not an official act”

In this thought experiment, they would certainly not be able to say that because they wouldn’t exist anymore.

Any new justices would certainly certainly hold the Biden-preferred opinion, because otherwise he wouldn’t nominate them. (That opinion would neither be “Biden is immune and this is fine” nor “that was not an official act,” but rather “we’re overturning the previous decision and making the President prosecutable for illegal official acts again,” because forcing that ruling would be the entire point of the exercise, BTW.)